Hot Tubs & Spas: Cutting Energy Costs

There are an estimated 3.5 million spas and hot tubs in the United States, about half a million in California alone! Each spa can use around 2500 kWh of energy per year – that’s almost 9 Billion Kilowatt hours!

This has caused various state and federal energy agencies to look closely at the way spas and hot tubs are designed, and how this affects their energy consumption. Several studies have been done in the last ten years, and they give us a good idea of where manufacturers and citizens can save energy around a spa or hot tub.

From a study commissioned by PG&E, for instance, we know that there are measures that can improve spa efficiency by up to 40% for spas of average to low efficiency. States with scarce power supplies (like California), are very interested in reducing demand on the grid.

The study aforementioned was responsible, in 2006 for the insertion of spas and hot tub standards being inserted into Title 20, California’s energy saving initiative. This set efficiency standards for new spas and hot tubs, similar to the cafe standards, which mandate minimum mpg for automobile manufacturers.

The standards have been revised and tweaked, and as a result of more research we now know more about how spas and hot tubs use energy. Here’s what we’ve learned:

Top 5 ways to Reduce Hot Tub Energy Costs

LIGHTS: Starting the list are our spa light or lights. Using LED lights, with a consumption around 3 watts, beats out halogen or other bulbs as the way to go. Most new spas are entirely LED, with some exception. Older spas can retrofit to use LED bulbs, in some cases without changing the light housing, or replace with a spa light kit. If your spa light does not have an auto shut off, install an indicator light in the circuit that you can see from the house, to keep off when not being used.

Possible Energy Savings: 5-10%

CONTROLS:Smarter control systems are now possible, with pumps that have a dozen programmable speeds, and timer clocks that allow you to optimize energy usage with multiple run times, programmed for your usage patterns, and taking advantage of cheaper off peak energy. Most spas are programmable, even if they have a mechanical time clock – but many people fail to optimize it.

It takes a lot of energy to start the pump motor and heater, extra amps aid in the starting-up, so although many daily on-off cycles are good, too many can be too much. For your spa, Experiment by reducing the hours, to find a sweet spot where the water quality or temperature won’t suffer, and you can cut energy costs. You don’t need to run it 24 hours a day!

Run the pump(s) less during the day, to avoid peak usage hours. My spa pump mostly runs on low speed, but it takes a long break in the morning and then another mid-afternoon siesta.

If you have two pumps, you have one smaller circulation pump, and a larger jet pump. Experimenting with run times on these can also result in savings.

Possible Energy Savings: 10-20%

PUMP: Running your pumps less helps yes, but for those spas out there with the 20 year old pumps, or the single speed pumps, or the pumps that suddenly disabled their low speed, or the failed circulation pump that was never replaced. I’m talking to you!

Replacing with the most current spa pumps will give you a boost in economy with a more energy efficient motors used nowadays. Side discharge pumps also have a boost in efficiency over center discharge.

Possible Energy Savings: 10-20%

COVER: Your spa cover can either be saving you money, or costing you money. If you can see steam creeping out of the edges of it, or if your cover has taken on water, it’s not holding the heat in like it should.

The heat retention in a spa cover has to do with 3 things, the density of the foam, the thickness of the foam and the foam core wrap or seal. Although we offer a 1.5lb spa cover, a 2.0 foam density is best for holding heat in, with a taper of 3 to 5 inches at least. And when you order your next replacement spa cover, go for the options of the double wrapped foam core and the continuous heat seal – worthy add-ons that will save heat and protect your core from moisture.

Possible Energy Savings: 15-20%

INSULATION: And now, drum roll please – the most significant thing you can do to increase your spa or hot tub energy efficiency is to make sure your tub is well insulated underneath and around the sides. There are many portable spas that have virtually no underside foaming, and have a thin sheet of padding on the inside of the cabinet walls. Hot tubs, true wooden tubs don’t normally have any insulation around the outside and can be extremely inefficient, which is why most are heated on demand, and not kept hot.

You can increase your spa’s efficiency by stuffing bats of fiberglass insulation everywhere you can under the spa, with the exception of the air space around the spa equipment. You can also use spray foam to fill in gaps, and eliminate air spaces and gaps – but it would be easier to use removable insulation, especially for future access to pipes or jets around the spa.